Hewlett-Packard z556 Digital Entertainment Center

This media-center PC has a lot of potential, but watch out for incompatibilities with consumer displays.

The Media Center shell is the onscreen interface/menu system that lets you access all the various types of available content, including TV (live and recorded), DVD, photos, music, video (downloaded and personal), and FM radio. It also provides access to system settings and other mediarelated items. In general, the Media Center menu system is well designed and logical.

The electronic program guide (EPG) is also very well-designed, showing you a grid of the programs on each channel, both analog and digital. The grid extends two weeks into the future, and you can jump ahead three or 12 hours at a time by pressing the FAST FORWARD or SKIP FORWARD buttons, respectively, which is great.

When you select a show that is currently in progress, it is displayed full screen; if you select a show in the future, a screen appears that lets you specify if you want to record just that episode or the entire series. You can also display a list of other showings and perform various advanced functions.

My only real complaint with the user interface is that it sometimes took many seconds for the DEC to do what I asked of it. Meanwhile, I was left wondering if the command was received (a spinning icon indicates that the computer is thinking, but it’s not always displayed) or if the computer had crashed (which it did on a couple of occasions).

Performance

The “Start Here” documentation recommends not using a DVI connection during the initial setup, though it’s not clear why. I connected the VGA output to the SIM2 HTL40 LINK LCD display I was reviewing at the same time (see page 98) and fired up the DEC. The set-up procedure presents a series of questions, which took only a few minutes. Then, the computer reboots and goes through the display setup. I specified a 16:9 screen, but the image remained in a 4:3 window. I was able to fix that by adjusting the display’s size and position controls.

Next, the Windows desktop appears for a while, followed by the Media Center Setup Wizard. Oddly, the automatic signal-detection routine didn’t think there was an RF source connected (there was), so I engaged the manual channel-scan routine, which found all the ATSC channels I can receive and indicated the signal strength of each one. I later learned that the auto signal-detection routine only scans for analog channels, and I had not connected my analog cable feed. This seems like a design oversight to me.

When I first tried to watch TV, all I got was snow. A call to HP revealed that ATSC channels are numbered differently than I imagined; for example, digital channel 2-1 is specified as 1021. Silly me! Since I had not connected my analog cable feed, calling up channel 2 resulted in snow.

After setup, I tried a DVI connection, which didn’t work very well at all—the resolution was wrong and the colors were all screwed up with a heavy green bias. After speaking with an HP rep, I learned that the DEC expects the display to send a message called EDID (Extended Display Identification Data), which tells the computer about the display’s capabilities. Computer manufacturers routinely implement EDID in their monitors, but consumer-electronics manufacturers are not used to doing so in TVs. As a result, some displays send incomplete or incorrect information or no info at all.

Apparently, the HTL40 sends the correct EDID via VGA, but not DVI, which reports a resolution of 1280x720; also, something in that information really whacked out the color. So I went back to VGA and stayed there for the remainder of the review period.

HDTV and DVDs

Once everything was up and running, I concentrated on HDTV and DVD viewing. HDTV looked wonderful for the most part, with rich colors and surprisingly deep blacks, even on an LCD flat panel. Asking the HP rep about this, I learned that the DEC stretches the brightness scale from its normal video range of 16 to 235 to the maximum possible range of 0 to 255. This increases the dynamic range of the image and helps displays that are black- and/or white-challenged, but it also eliminates the possibility of displaying information above white and below black.

HP contends that there is no information in these regions of normal video programming anyway, but others insist there is, especially in certain types of programs, such as sports.

This technique does make the picture look mighty good, but it can lead to some trouble. For example, the Media Center software includes routines to help adjust the user controls of the display, including so-called belowblack information. But these elements can’t be seen when played from the DEC because of the dynamic-range expansion. Thus, you must use another source to set the display’s brightness and contrast controls.

After watching for a while, I noticed one significant problem: During horizontal motion (either camera pans or moving objects), the top two inches of the image appeared to separate and lag behind the rest of the picture. The faster the motion, the greater the disparity between the two regions. The boundary between the two regions was very sharp, and the effect disappeared when the motion stopped.